Preparation of 7-substituted-1-(2-diethylaminoethyl)-5-(2-halophenyl)-1,3-dihydro-2h-1,4-benzodiazepin-2-ones

ABSTRACT

7-Substituted-1-(2-diethylaminoethyl)-5-(2-halophenyl)-1,3dihydro-2H-1,4 -benzodiazepin-2-ones are prepared starting with a 4-substituted-2-(2-halobenzoyl)aniline by a multi-step procedure. The product compounds produced by the process of the present invention are useful as tranquillizers, muscle relaxants, anticonvulsants and hypnotics.

United States Patent yer et al. 1431 Sept. 12, 1972 [54] PREPARATION OF 7-SUBSTITUTED-l- 3,284,503 Ill 1966 McMillan et al....260l239.3 D (2-DIETHYLAMINOETHYL)-5-(2- 3,299,053 1/ 1967 Archer et al ..260/239.3 D HALOPHENYL)-l,3-DIHYDRO-2H-1,4- 3,304,313 2/1967 McMillan et al....260/239.3 D BENZODIAZEPlN-Z-ONES 3,371,085 2/1968 Reeder et al ..260/239.3 D 3,391,138 7/1968 Archer et al ..260/239.3 D [721 g z' f g g gkf im g: 3,510,517 5/1970 Richter et al ..260/570 AB bull, l0 Woodmont Road, pp FOREIGN PATENTS 0R APPLICATIONS Montclair, NJ. 07043 204,435 8/1939 Switzerland ..260/570 AB [22] led: 1,970 206,612 11/1939 Switzerland ..260/570 AB [21] Appl, No.; 63,273 206,613 11/1939 Switzerland ..260/570 AB Related Application Data Primary Examineri-lenry R. Jees [63] Continuation-impart of Ser. No. 733,817, June Assis'am Bond 3,1968abandoned. Attorney-Samuel L. Welt, Jon S. Saxe, Bernard S.

Leon, William G. lsgro and Margaret C. Bogosian [52] U.S. Cl......260/239.3 D, 260/562 N, 260/562 P,

. 260/570 AB, 260/326 D, 260/326 N, ABSTRACT I l I 2150/99) 7-Substituted-l-(2-diethylaminoethyl)-5-(2-halophen- .{g y 3 y 2 4 i pi z are 0 I prepared starting with a 4-substituted-2-(2- halobenzoyl)aniline by a multi-step procedure. The [56] References Cmd product compounds produced by the process of the UNITED STATES PATENTS present invention are useful as tranquillizers, muscle 1 ts, t 1 ts d h n t 3,192,199 6/1965 McMillan 6131....260/2393 D am 1 com San an yp 0 3,221,050 11/1965 McMillan et al....260/239.3 D 6 Claims, No Drawings '1 2 PREPARATION OF 7-SUBSTITUTED-l-(2- where X, X, n, R, and R are as above. DIETHYLAMINOETHYU-SaQ-HALOPHENYIJ-l,3- The next reaction step of the present process in- DIHYDRO-ZI-I-l,4-BENZODIAZEPINqZ-QNES volves the simultaneous reduction of both carbonyl functions in the compounds of formula IV above utiliz- RELATED APPLICATIONS ing a chemical reducing agent, e.g., lithium aluminum This application is a continuation-in-part application yd 5 3. to p d a compound of the formula: of Ser. No. 733,817 filed on June 3, 1968, now abandoned. R1

' -NH(CI-Iz)nN DETAILED DESCRIPTION OF THE INVENTION 10 I The present invention relates to a process for the X 417K011 preparation of compounds of the general formula:

( Q H u 1 5 0 R2 ll NC where X, X, n, R, and R are as above. "The compounds of formulaV are then treated with a X a 1 selective oxidation agent so as to reconvert the hydroxi -yl group to a ketone'function. Suitable oxidation agents X', 1 for this purpose include, for example, MnO Q0 8e0 AgO, and the like.

The resulting product from the aforesaid oxidation v a 1 reaction corresponds to compounds having the followwherein R and R, are lower alkyl, X and X are mg fQrmul-a:

hydrogen, halogen and trifluoromethyl and n is an integer from 2 to 5 by a multi-step synthesis starting with compounds of the general formula: (C 2)I1 R x c=o -NH2 x! x -'a=0 11 40 where X, X, n, R and R are as above,

where X and are as above Compounds of formula VI above are treated with The initial Step in h above described Synmesis phthalumdoacetyl chloride to produce a compound of volves reacting a compound of the formula II above formulavubebw: with a haloalkanoyl halide represented by YCO (CI-I Y, where Y is halogen, e.g., bromoacetyl bromide, to

produce a compound of the formula III below:

x -o=o o .x' H

, a, VII where X, X and n are as above and Y is halogen. The compound of formula III above is then treated with a di-lower alkylamine represented by HNRgRz where R, and R are lower alkyl such as, for example, where X and are as above In a final step of the present reaction sequence, the 1 33 33 gi fi i iz fgg to form a com' phthaloyl group is removed and the intermediate cyclpo iaed to form a benzodiazepine ring structure. The removal of the phthaloyl group is effected by treatment NHGO(CHa)n-1N with hydrazine and the cyclization occurs in situ to l form compounds of the formula I above. X In order to more clearly indicate the reaction sequence to which the present invention is directed, the following reaction scheme is provided. In this reaction scheme, the meanings of X, X', n, R R and Y are as W above throughout.

The reaction conditions and selection of solvents for 0 each of the respective reactions identified in the above Reaction Conditions reaction scheme by a capital letter under the cor- Reaction responding arrow are summarized below in Tablel. it?" Reaction conditions include both operative values and A 50 g() any fg- Benzene preferred ranges. Similar designations for operative 65 p-' and preferred are giventfor the solvents useful in each reflux temp. of

of the enumerated reactions. t solvent preferred embodiment of the present invention, Y is B below room 2030 any inert org- Dichlorotemp. at 'anic solvent methane atmospheric to 160 in an auto clave C room temp.35-80 any ether such Tetrahydro 5 to reflux as ethyl ether furan temp. of butylether solvent tetrahydrodrofuran D to at or abany inert v Chloroform 100 out room solvent Acetic acid temp. E room temp.60-80 any inert org- Tetrahydroto reflux anic solvent t'uran temp. of Benzene solvent, F, l0?to reat or abany inert org- Ethanol flux temp. out room anic solvent Chlorofonn of solvent temp.

All temperatures are in degrees Centigrade bromine, X is chlorine,X' is fluorine, n is 2 and R, and R are each ethyl as above. Thus, the desired end product of the present process in its most preferred embodiment may be represented by the following formula:

CHz-CH;

CHz-N (EH2 El) CHz-CHa N-C VIII The term lower alkyl as used herein is meant to in clude both straight and branched chain groups having from one to seven, preferably one to four carbon atoms. Examples of representative lower alkyl groups include methyl, ethyl, propyl and isopropyl. The term "halogen, as used throughout the present disclosure, is intended to connote all four halogens, namely, chlorine, bromine, iodine, and fluorine, unless otherwise specified.

It has thus been demonstrated that the process of the present invention is useful in preparing compounds which correspond to general formula I above. Such 55 compounds have been shown in the art to exhibit important pharmaceutical activity, particularly with reference to their use as tranquillizers, muscle relaxants, anti-convulsants and hypnotics. An example of a typically 'efi'ective compound in this series is represented by the compound of formula above, i.e., 7-chlor0-1-(2-diethylaminoethyl)-5-(2- fluorophenyl)- l ,3-dihydro-2H- l ,4-benzodiazepin-2- one.

The present invention may be more clearly understood with reference'to the following samples which are presented for the sake of illustrationand are not meant to limit the scope of the present invention in any manner. All temperatures in these examples are in degrees Centigrade.

EXAMPLE 1 Preparation of 4'-Chloro-2-diethylamino-2-(2- fluorobenzoyl)-acetanilide A solution of g. (0.202 m) of 2-bromo-4-chloro- 2-(2-fluorobenzoyl)acetanilide in 325 ml. of dichloromethane was treated with 17.7 g. (0.242 m) of diethylamine. After standing overnight at room temperature another 17.7 g. of diethylamine was added and the mixture was allowed to stand for an additional 2.5 hours. The solution was washed with 500 ml. of water, 200 ml. .of saturated brine solution, stirred with charcoal and anhydrous sodium sulfate, filtered and evaporated to dryness.

The residual oil was dissolved in 150 ml. of benzene and filtered through 400 g. of Fluorisil. The product was eluted with benzene followed by ether. The ether fraction was concentrated and the product recrystallized from ether, and the from a mixture of ether and petroleum ether to give the above-titled compound as white prisms, melting point 4859. The benzene fraction was evaporated to give additional product as an oil, which was not further purified but used directly in the subsequent steps.

' EXAMPLE 2 Preparation of 5-Chloro-2-( 2- diethylaminoethylamino)-2'-fluorobenzhydrol A solution of 8.7 g. (0.229 m) of lithium aluminum hydride in 200 ml. of dry tetrahydrofuran under nitrogen was cooled in an ice bath and treated by the dropwise addition of a solution of 55.6 g. (0.153 m) of 4'-chloro-2-diethylamino2'-(2-fluorobenzoyl)acetanilide in 150 ml. of dry tetrahydrofuran. The reaction was stirred overnight at room temperature andthen heated under reflux for one hour. An additional 5.8 g. (0.153 m) of lithium aluminum hydride was added and the reaction mixture was heated under reflux for one hour, cooled'to room temperature when excess reagent was decomposed with 10 ml. of water. A saturated solution of sodium bicarbonate was added until the emulsion coagulated. The precipitate was removed by filtration over Celite and washed with dichloromethane. The filtrates were combined and evaporated to dryness to give the above-titled compound as an oil, which was used without further purification in subsequent reactions.

EXAMPLE 3 Preparation of S-Chloro-2-(2- diethylaminoethylamino)-2'-fluorobenzophenone A solution of 5 g. (0.142 M) of 5-chloro-2-(2- diethylaminoethylamino)-2'-fluorobenzhydrol in m1. of xylene was treated with 6.1 g. (0.071 M) of manganese dioxide and the mixture was stirred and refluxed for 6 hours. The solution was filtered nd. distilled to dryness under reduced pressure.

The residual oil was dissolved in 15 m1. of benzene and chromatographed on g. of silica gel. The column was eluted first with 500 ml. of benzene and 500 ml. of dichloromethane. Both fractions were discarded and then the column was eluted with 300 ml.

of ether. The ether fraction was treated with an excess of ethanolic hydrogen chloride, distilled to dryness and the residual oil was crystallized from a mixture of isopropanol and ether to give the above-named product as yellow needles, mp. 130138.

EXAMPLE 4 Preparation of 4'-Ch1oro-2'-( 2-fluorobenzoyl)-N (2- diethylarninoethyl)-2-phthalimidoacetanilide hydrochloride A solufion containing 4 g. (0.0114 m) of 5-chloro-2- (2-diethylaminoethylamino)-2'-fluorobenzophenone and 5 g. (0.0228 m) of phthalimidoacetyl chloride in 50 ml. of tetrahydrofuran was heated under reflux for 17 hours, and then evaporated to dryness. The residue was made basic with a sodium bicarbonate solution, and the product was extracted into dichloromethane (3 X 100 ml.). The organic layers were combined, washed with 100 ml. of saturated brine, dried over anhydrous sodium sulfate and evaporated to dryness.

The oil was dissolved in 100 ml. of benzene and an excess of ethanolic hydrogen chloride was added, and the resulting solution was evaporated to dryness under vacuum. The salt was crystallized from isopropanol, and then from a mixture of methanol and ether to give the above-titled product as white prisms, melting point 268-274 (sealed tube).

EXAMPLE 5 Preparation of 7-Chloro-1-(2-diethylaminoethyl)-5-(2- fluorophenyl)-1 ,3-dihydro-2H-l ,4-benzodiazepin-2- one A solution of 2 g. (0.0037 m) of 4-chloro-2'-(2- fluorobenzoyl)-N-(2-diethylaminoethyl)-2- phthalimidoacetanilide in 30 ml. of ethanol and 30 ml. of chloroform was treated with 0.55 g. (0.11 m) of hydrazine hydrate, and the solution was allowed to stand for 17 hours. The reaction mixture was evaporated to dryness, made basic with 100 m1. of dilute ammonium hydroxide and extracted with ether (2 X 200 ml.). The ether layers were combined and extracted with 150 ml. of Spercent hydrochloric acid, which was then made basic with ammonium hydroxide and extracted with 200 ml. of ether. The ether layer was washed with saturated brine, dried over anhydrous sodium sulfate and evaporated to dryness. The residual oil was crystallized from a mixture of ether and petroleum ether to give the above-titled product as white rods, melting point 80-84.

We claim:

1. A process for the preparation of compounds of the formula:

wherein R, and R are lower alkyl, X and X are hydrogen, halogen and trifluoromethyl and n is an integer from 2 to 5 which process comprises the following steps in combination:

A. reacting a compound of the formula:

where X and X are as above with a haloalkanoyl halide;

B. reacting the product from (A) above with a lower dialkyl amine;

C. reducing carbonyl functions in the product of (B) above with lithium aluminum hydride to yield a benzhydrol compound;

D. treating the aforesaid benzhydrol with a selective oxidation agent selected from the group consisting of manganese dioxide and chromic acid to produce the corresponding benzophenone;

reacting the above benzophenone phthalimidoacetyl chloride; and F. treating the phthalimidoacetyl derivative with hydrazine to effect removal of the phthaloyl group and cyclization to a benzodiazepine ring structure. 2. The process of claim 1 wherein said halo alkanoyl halide of step (A) above is bromoacetyl bromide.

3. The process of claim 1 wherein said lower dialkyl amine of step (B) above is diethylamine.

4. The process of claim 1 wherein n has a value of 2 and X and X are each halogen.

5. The process of claim 6 wherein X is chlorine and 6. The process of claim 1 wherein n is 2, X is chlorine, X' is fluorine and R, and R are each ethyl.

E. with UNITED- STATES PATENT OFFICE CERTIFICATE OF CORRECTION Ratent: NO. 5,691,157 Dated S p m r 12, 1972 Inventofls) Rodnev Ian Flower and Leo Henrvlg fiternbach It is certified that error appears in the above-identified patent I and that said Letters Patent are hereby corrected as shown below:

No assignee in case should be assigned to Hoffmann-La Roche Inc.

The process of claim .4

Signed and sealed this 1st day of May 197 3.

(SLJAL) EDWARD FLETCHER, JR ROBERT GOTTSCHALK Attesting Officer I Commissioner of Patents I FORM PO-105O (10-69) USCOMM-DC 60376-1 69 h uds. sovcmmzln Pmmuc ornc: 19 o-au-an 

2. The process of claim 1 wherein said halo alkanoyl halide of step (A) above is bromoacetyl bromide.
 3. The process of claim 1 wherein said lower dialkyl amine of step (B) above is diethylamine.
 4. The process of claim 1 wherein n has a value of 2 and X and X'' are each halogen.
 5. The process of claim 6 wherein X is chlorine and X'' is fluorine.
 6. The process of claim 1 wherein n is 2, X is chlorine, X'' is fluorine and R1 and R2 are each ethyl. 